Process and apparatus for the manufacture of artificial filaments



May 3,1932. E 1,856,401

PROCESS AND APPARATUS FOR THE MANUFACTURE OF ARTIFICIAL FILAMENTS Filed June 14, 1924 l gQ/www llrromns Patented May 3, 1932' ,jgfumrso STATES PATENT OFFICE i EDMOND PRINCE, OI TASSIN-IA-DEII-LUNE, FRANCE, ASSIGNOR, BY MEBNE ASSIGN- MENTS, '10 DU PONT RAYON COMPANY,

DELAWARE 01 NEW YORK, N. Y., A CORPQRATION OI PROCESS AND APPARATUS FOR THE MANUFACTURE OF ARTIFICIAL EILAIENTB Application filed June 14, 1924, Serial No.

The present invention relates to improvements in processes and ap aratus intended for the manufacture of arti cial filaments of all kinds constituted either by a single fibre 5 or by the union of several fibres, obtained by a flowing or spinning, in a gaseous medium, whether heated or not, of a more or less VIS- cous fluid of suitable composition, comprising essentially:

(1) A solvent or solvent mixture (A), volatile in the operating conditions which are selected for spinning the said fluid.

(2) A body or mixture of bodies (B), suitably selected, non-volatile in the operating conditions adopted for spinning, which, when freed by evaporation of the liquid or mixture of liquids (A), constitutes the substance of the artificial filament issuing after spinning,

(B) being constituted, for instance, by an ether, an ester, or another derivative of cellulose, alone, or mixed with other ethers, esters, or cellulose derivatives, or else by a derivative or mixture of derivatives of cellulose with substances adapted to impart plasticity or non-volatile solvents of the said derivatives. The mixture (B) may be, if desired, such as also to comprise in every one of the above placed, at one of its ends, the spinning device or die which comprises essentially apertures or orifices the number, shape, and diameter of which is adapted to the kind of threads or filaments which it is desired to manufacture, and at the other end the orifice or orifices for the exit of this or these threads or filaments.

Through the cell passes a current of air or other gaseous medium intended to enhance the evaporation of the solvent or solvent mix ture and heated by any suitable means, either outside the cell or inside the latter, or both outside and inside, simultaneously, as has been described, for instance, in the casev of 720,108, and in France December 21, 1923.

downward s inning onl in my pending application iarial No. 66;:872, filed October 4 As has been described in the above mentioned application, the heating may be arran ed, or be performed, in such a manner as to o tain a suitable uniform temperature for the whole of the inside of the cell, or, on the contrary, to obtain different temperatures at different levels in the cell, for instance, in such a way as to have a lower temperature at' the spinning device, so as not to affect the proper working thereof,

The process most generally used consists in passing through the cell, heated or not as the case may be, the evaporating gaseous medium, either already warmed or merely at ordinary temperature, the said medium en tering by the outlet orifice or orifices of the thread or threads or filament or filaments, or by openings provided in the portion of the walls or the cell which is in the vicinity of these orifices. The gaseous current will then pass through the cell, will become loaded with the vapours of the solvent or solvent mixture (A) and issues from the cell by the.

opposite end of the latter, that is, that nearest the spinning die or dies. I

Care is taken to maintain all the conditions obtaining during the spinning asconstant and regular as possible by any suitable means, and, particularly, to regulate the rate of flow of the selected gaseous medium and its heating, whether before entering or in-- side the cells, in as uniforma manner as possible.

In spite of these precautions,

the spimling is often unsteady, that is,

the elementary fibres break frequently inside the cell. This unsteadiness is the cause of important su plementary expense, not only owing tot e labour necessitated by the operation of gathering the broken elementary fibre or fibres and again joining them, when required, to the other fibres forming the manufactured filament" or filaments, but also by the perturbations which are caused by this operation in the spinning and the proper recovery of the solvents. This drawback increases, of course, when the fibres which it is desired to obtain become very fine and have thereby less resistance, or when it is sought to increasethe speed of spinning, thereby increasing the efforts to which the fibres are subjected.

The unsteadiness of the spinning has therefore the further objectionable effect of either preventing the manufacture of threads or filaments formed of very fine elementary fibres, or compelling a reduction of the speed of spinning, which diminishes the output of the plant and increases therefore the cost of production.

The arrangement mentioned pending application does away with or diminishes, the drawbacks" of the unsteadiness, but does not improve the steadiness of the spinning itself.

An efiicient regulation of the heating and of the rate of flow of the gaseous medium improves considerably the steadiness of the spinning in an industrial installation. It doesnot, however, remove all the causes of rupture of the fibres. Y

I have made the very important observation that one of the principal, if not the principal, cause of unsteadiness in spinning resides in the fact that in all the processes hitherto known, the temperature of the medium in the vicinity of the spinning dies is relatively high. In order to facilitate the evaporation of the solvent, this medium is heated, as has been mentioned above, in such a manner that the manufactured threador threads, filament or filaments, issue from the cells with the necessary degree of dryness.

Although part of the heat so supplied to the gaseous medium is absorbed in the evaporation of the volatile solvent or solvents used, there remains generally in the said medium a notable excess of heat, so that its temperature at the exit from the cells is always higher (notably higher in some cases) than the can ternal temperature.

An elevation of the temperature in the vicinity of the-spinning dies has for its effect to diminish to a rapidly increasing extent the viscosity of the solution being spun, and, therefore, the resistance of the fibre being formed, which still contains all or most of the volatile solvent or solvents (A).

This drop in the resistance has an obvious connection with the rupture of the fibre or V fibres, particularly when the spinning takes place near the practical limit of resistance,

that is, when these fibres are very fine or when the speed of spinning is high Accordingto the present 1 steadiness of the spinning is increased, or,

what comes to the same thing, finer fibresmay bespun or a higher speed of spinning may be adopted with the same steadiness and therefore products of superior economicai value may be obtained in the best conditions as to cost of production, by lowering. the

described in my above nvention, the

tiamperature in the vicinity of the spinning 18S. This lowering of the temperature may be obtainedin any suitable manner, and particu- 'larly by the following means, which may be combined in any proportion and in any desirable manner:

(1) The spinning fluid may be cooled down to a temperature as lowas may be desired, by any known method, either before it reaches the spinning dies, or in the immediate vicinity of the latter, or both these courses ma be used simultaneously.

2) A suitable cooling arrangement may be placed in the cell or outside the latter, in the vicinity of the spinning dies, the cooling bein obtained by any suitable process such as, or instance, by providing the wall, if thermally conducting, any other device adapted toradiate heat or by providing a jacket in which a cooled fluid is caused to flow, or else by placing in the cell coils, ribbed tubes or other radiating devices in which flows a cold fluid, or by means of several or all of the above processes.

(3) The length of the cells may be increased in the direction of the spinning; this will allow, all other conditions remaining the same, the diminishing of the maximum temperature to which the gaseous medium employed must be brought, and therefore also the temperature at which this medium issues from the cells. I

(4) The dryin medium may also be in troduced in the cel in the vicinity of the spinning dies, it may be exhausted near the exit of the threads or filaments from the cell, the medium being, or not being, heated in the Whole of the region of-the cell which is adapted for the drying.

(5) Lastly, the desired result may be obtained by causing the gaseous medium loaded with the volatile solvents to issue from the cell at a region suitably chosen, intermediate between the spinning dies and the exit of the threads or filaments. The admission of the aseous medium may then take place either thegvicinity of the spinning dies is cold or is at ordinary temperature. it may, howe ver, be introduced at any suitable temperature for any desired purpose.

I have, as a matter of fact, discovered that this procedure presents the following important practice advantages:

. It is easy to obtain or to select, for intro- Preferably the atmosphere introduced in 1 ducin it in the neighbourhood of the spinning 1es, a gaseous medium the temperature of which is strictly uniform, or only undergpes' slight variation over long periods of time. It is so, for example, if the said gaseone medium is the atmosphere of the spin- ,nings'hed itself, or if it is heated or cooled in a suitable manner.

As,- on the other hand, care will be taken to maintain all the other conditions obtaining while spinning constant or nearly constant, the spinning will be performed under re-- markably uniform conditions and, therefore,

- the elementary fibres will be of very uniform dimension and quality.

Such a result cannot be obtained with the Spinning processes hitherto used, whatever care may be bestowed upon the factors infiuencing thespinning. For instance, the temperature. of the medium in which the spinning process takes place, that is, the temperature at which the gaseous medium issues from the cell, is subjected, in those processes, to variations which are slight, but which are erratic and of short periods, due, for instance, to variations in the rate of fiow of the fluid to be spun, or of the gaseous medium used, the latter being then more or less cooled owing to the heat absorbed by the evaporation of the solvent or solvents or to variations in the degree of dryness of the fibres due to any cause, or to variations inherent to the'heating systems usually employed, whether carried out within the cell or outside the latter, or, most frequently, to variations arising out of all the above causes simultaneously. The

\ results of these variations are irregular variations of short riod in the standard of the manufactured t reads or filaments. On the other hand, threads or filaments obtained by means of the arrangement which I have discovered, tested by the same apparatus, have proved to be much more regular, and this even when, all other conditions remaining the same, the rate of flow of the gaseous medium used for the drying of the threads or filaments and entering by the orifices for the exit of said threads or filaments, or in the vicinity of these orifices, was allowed to vary between wide limits.

Without excluding any of the above-mentioned devices for the cooling of the gaseous medium in the vicinity of the spinning dies, and even if it were not desired to submit the said region of thecells to any cooling, it is preferred, for the above-mentioned reason, to, cause the gaseous medium to leave the cell at a region intermediate between the spinning dies and the exit orifices of the threads and filaments, and to introduce in-the cell, simultaneously, by the portion near the said exit orifices and that in the vicinity of the spinning dies, either the same gaseous medium,

or two difierent gaseousmedia, which may be at the same or at different temperatures.

Concerning the gaseous medium introduced by or in the vicinity of the exit orifices of the threads or filaments, it may be brought in any manner to any desired temperature, before its admission to the cell. It may be referable, however, to introduce it cold in t e cell, for, by operating in this manner, and if the length of the cell is suflicient, not only the manufactured threads or filaments will leave the cell with the desired degree of dryness, but they will moreover issue from the cell as cold as possible. This has several practical advantages, among which may be mentioned the decrease of intensity of the objectionable electrification phenomena which usually take place during spinning of cellulose derivatives.

It will be understood that my invention is applicable to most varied types of cells, either isolated or united in groups more or less important, and whatever may be the manner in which the are constituted, the number or the form of t e threads obtained in each cell or of the elementary fibres of each thread or filament,- and the nature of the cellulose derivative, of the solvent or solvent mixture or of the various additive substances employed.

It is applicable just as well if the spinning takes place downwards in the cells, or u wards or in any other manner, and it is o vious that any treatment may further be applied tothe manufactured threads or filaments after they have issued from the cell or cells. The arrangements adapted to carry it out may be of any suitable description. Preferably, the inlets for the air or for the selected gaseous medium, and which may be, or not, adjustable, are regularly distributed so as to distribute the gaseous stream in the best possible manner. The same applies to the outlet orifices for this medium, the exhaust taking place so as to avoid carrying away the elementary fibres, which are very light, by one or several openings, or'also, for instance, by means of a collector surrounding the cell, as described in the example hereafter, orby any other distributing system having the same purpose.

' The distance provided between this exit, on the one hand, and the spinning dies or the exit orifices of the filament or filaments on the o her hand, may vary between lar e limits. It depends upon the special con itions in which spinning takes place, such as for instance the length of the cell, the constitution of the solutions employed, the natul'e of the solvent or solventsfthe form and the dimensions of-the spun fibre or fibres, the selected:

ney through it, the selected gaseous medium, entering opposite the spinning dles, may be any suitable device,

tablished on the same principle, for instance,-

can be provided in the latter zone.

If the walls of the cell are thermally conducting, a thermallyl insulating joint may be provided between t e portion of the wall of the cell next to the spinning dies and next to the exit orifices, respectively.

Thermometers in suitable number may be provided to indicate the temperature at van- 7 ous points in the cell. The stream of air'or of the selected evaporating gaseous medium may be produced in any suitable manner, The air or gaseous medium may be sent in each cell by a blower, for instance, but preferably it will be, on the contrary, aspirated by connected after the cell, cell and the recovery for example between the or after the plant of the solvent or solvents, said recovery plant, if any.

Obviously this recovery of the solvents is an operation entirely independent of the spinning and may be dispensed with if economical solvents (A) are employed, or if their recovery is costly, or for any other cause. In this case, the selected gaseous medium after issuing from the cell and after passing through the aspirating device, if any, may be exhausted in the surrounding atmosphere, for example, on the roof of the shed, by means of a suitable exhaust pipe, or yet carried away by water or a liquid if, for instance, the aspirating device is a liquid (water) jet aspirator, or it may be exhausted in any other manner. If wished, scrubbing towers may be inserted in the exhaust for any desire purpose, such as to free the exhaust gases from any noxious or objectionable product before re ecting it in the atmosphere.

Whether or not the recovery of the solvent or solvents (A) is performed, the gaseous medium may be use over again if desired, that is, it may be sent again into the cell or cells after having been completely or artially freed from the solvent or solvents A.) "and restored to the conditions in which it is desired to use it normally, by drying, or, on the contrary, by moistening, heating, or cooling, partial exhaust and admission of fresh medium, or generally any other operation.

re-employment may be whole or gillgfifll. be ing limited for example to thefee g of the cell or cells on the side of the spinning dies,

or, on the contrary, on the side of theexit orifice or orifices of the threads or filaments. Of course, this re-employment cannot be applied to the ,exit orifices of the threads or filaments, but these orifices may be chosen of very small dimensions, or' may be provided with any suitable device, so as to minimize as t will be useless to provide also.

the purpose of (1 cell dispose 'eral alignment of the cells in the much as possible the corresponding re-entrance of the air.

If desired, the gaseous medium issuing from a cell may be used again, wholly or in part, for feeding the next cells, this being done, for example, next to the exit orifice or orifices of the threads or filaments only, for systematically increasing the amount of vapours of the volatile solvents in the said cells, or for any other purpose.

Generally speaking, the recovery of the vol-' atilesolvent or solvents (A) is advantageous, whether the gaseous medium is used over again or not. It may be carried out by any desired, usual, or known process, any su table devices, apparatus, or organs necessary ordesirable for the purpose being added to the cells or systems ofcells. It will be convenient in this case to be able to isolate, by any suitable means, any cell or group of cells the working of which is momentarily interrupted for any reason.

It is also desirable that the total flow of the gaseous medium through the cell be li ited to the strict necessary minimum, so that the proportion in volatile solvents of the medium issuing from the cell may be as high as possible, and to this end it is necessary to adjust suitably the rate of flow through each cell.

The said regulating devices, or any others which may be employed, are advantageously used, as is customary, in connection with any controlling device, such as thermometers, manometers, flow-meters, automatic analyzing apparatus, sampling taps, etc. Bafiles may also be provide for the purpose of minimizing eddies in the cell.

The appended drawing represents diagrammatically, as an example only, a single d according to this invention, and adapted for vertical downward spinning, and

ati le solvents, the gaseous atmosphere utilized for carrying away the vapors of these solvents being the air of the sheds, and the -.fluid to be spun being a solution of acetate of cellulose in a, mixture of acetone and of ethyl alcohol. The figure is a section along a plane along the axis, and perpendicular to the gen- 1 is the wall of the cell prefers. ly c ylindrical and of metal, and formed of sections 1a and 1b, suitabli connected to one another by means of a. t ermally insulating joint 1c, the whole being supported by a suitable irame, not shown. v I

2, 2a, are heating jackets with the same heating area, connected to a water circulating system, the water entering by inlets 3, 3, and issuing by outlets 4, 4, said inlets and outlets being preferably in series, said jackets, inlets and outlets being externally thermally III The dotted lines 15,

i 7 or to'one of its parts. The air 0 the enters the cell at the same time by the outinsulated by lafigging 5, 5. Thermometers 6, 6, placed at di erent levels, allow any variation of the temperature inside the cell to be ascertained.

'7 is a spinning die, formed of 5......1 elementary spinning dies, nozzles or spinnerets 7a, 7a, said spinning die. 7 being pivoted about the axial support 8 in the stufling box 9. It receives, by the piping 10, the solution of cellulose acetate in a suitable mixture of ethylalcohol and acetone, which it is desired to spin into filaments, said solution being sup lied by means of any suitable device adapted to this end, and'provided with any 7 the polished surface of which may slide the the spun. filaments.- 12' is the outlet for the thread, comprising a perforated bronze member 13, made in two portions, and placed at the apex of the cone; 14 is a door to WlllCh is secured one of the portions of the outlet 13.

represent isolated filaments, forming by their reunion the thread 16 which, after passing through the delivery device 17 proceeds to any suitable and desirable apparatus for bobbining, twisting, etc.; devices for impregnating, etc.,

a may also be provided, either before or after the delivery device 17. 18 is a roll placed under the orifice 12, and rotated by any suitable means, not shown, on which the thread 16 winds itself when it is broken outside the cell, either accidentally or purposely. 19 is a small door giving access to the sp nnigldie s eds let 12, or also, simultaneously by openings 20 and 20', provided in the conical member 11, and by openings 21 provided above the spinnerets in the upper portion of the cell. In the upper portion of the cell and preferabl in the vicmit of the die, there is provide an inlet 27 w 'ch is connected to any suitable source of sup 1y as a reservoir 28 containing air or any other gaseous medium ofthe desired composition of appropriate temperature, whereby the temperature in the en-,

vironment of the die may be modified independently of the rest of the cell. The air laden with the voltaile vapours is aspirated by the tube or tubes, such as 22, opening into an annular chamber-23, so as to avoid the filaments being carried eous stream. The aspirated air could in the outside atmosphere, on the roof of the shed, for instance; if, however, it is desired to recover the volatile solvent with which it and aspirating the gaseous medium away by the gasbe led to exhaust is laden, the tube or tubes 22 are connected to a collector 26 by a joint 25 provided with an interchangeable diaphragm 24. The collector 26 is commonto a certain number of cells disposed in a similar manner. This collector may be provided with any desired accessory devices, and is itself connected to an air fan or pump, and to a system of apparatus for the recovery of the volatile ,solvents, not'shown.

What I claim and desire to secure by Letters Patent is 1. The process of manufacturing filaments or threads by dry spinning, which comprises causing a viscous fluid to be extruded from a spinning die directly into an evaporative atmosphere, and lowering the temperature of the fluid to be spun. r 2. The process of manufacturing filaments or threads by dry spinning, which comprises causing a viscous fluid to be extruded from a spinning die into an evaporative atmosphere in a-closed cell, admitting a gaseous medium into the cell in the vicinity of the spinning die, and admitting a gaseous medium of different composition into the cell at a point remote from the die.

v3. The process of manufacturin filaments or threads by dry spinning, w ich comprises causing a viscous fluid to be extruded from a spinning die into an evaporative atmosphere in a closed cell, admitting a gaseou s medium into the cell in the vicinity of the spinning die, and admitting a gaseous medium into the' cell at'a point remote from said die, the composition and temperature of the gas admitted in the vicinity of the die being different from the composition and-temperature of the gaseous medium admitted at the point remote from the die.

' 4. The process of manufacturing filaments or threads by dry s inning, which comprises causing a viscous uid to be extruded from a spinning die into an evaporative atmosphere in a closed cell individual to said spinning die, admittin a gaseous medium into the cell in the vicinity of the spinnin die, laden with a volatile constituent from are ion of the cell intermediate the spinning ie and thfi point of exit of the filaments from the co 5. The process of manufacturing filaments or threads by dry spinning which comprises causing a viscous fluid to be extruded from a spinning die directly into an evaporative atmosphere, and simultaneously lowering the temperature of the fluid to be spun before it reaches the die and in the vicinity of the die.

6. The process of manufacturing filaments or threads by dry spinning which comprises causing a viscous fluid to be extruded from a admitting a gaseous medium into the cellin the vicinity of the spinning die, and withdrawing the gaseous medium laden with a volatile constituent from a region of the cell intermediate the spinning die and the point 'of exit of the filament-or thread from the cell.

7. An apparatus for manufacturing filaments or threads by dry spinning compris ing a closed cell, a spinning die disposed in said cell, and means for simultaneously lowering the temperature of the fluid to be spun before it reaches the die and of .the atmosphere in the vicinity of the die.

' 8. An apparatus for manufacturing filaments or threads by dry spinning comprising a closed cell, a single spinning die disposed in said cell',means for admitting a gaseous medium into the cell in the vicinity of the spinning,

die, and means for withdrawing a gaseous medium laden with a volatile constituent from a region of the cell intermediate the .spinning die and the point of exit of the filament or threadfrom the cell.

9. The process of manufacturing filaments or threads by dry spinning which comprises causing a viscous fluid to be extruded from a spinning die directly into an evaporative atmosphere in a closed cell, and lowering the temperature of the fluid to be spun.

10. The process of manufacturing filaments Y .or threads by dry spinning which comprises causing a viscous fluid to be extruded from a spinning die into an evaporative atmosphere in a closed cell individual to said spinning die, admitting a gaseous medium into the cell in the vicinity of the spinning die, and admitting a gaseous medium to the cell in the region where the filament or thread issues therefrom.

11. The process of manufacturing filaments or threads by dry spinning which comprises or threads by dry spinningbwhich comprises causing a viscous fluid to e extruded from a spinning die into an evaporative atmosphere in a closed cell, admitting a gaseous medium into the cell in the vicinity of the spinning die, and admitting a gaseous medium to the cell in'the re on where the filament or thread issues there cm, the composition of the second gas being different from that admitted in the vicinity of the die.

' 13. The process of manufacturing filaments I or threadsby dry spinning which comprises causinga viscous fluid to be extruded from a spinning die directly intoan evaporative atmosphere in a closed cell, and simultane ously lowering the temperature of the fluid to be spun before it reaches the die and in the vicinity of the die.

14. The process of manufacturing filaments or threads by dry spinning which comprises causing a viscous fluid to be extruded from a mosphere in a closed cell, simultaneously lowering the temperature of the fluid to be spun before it reaches the die and in the vicinity of the die, and withdrawing the gaseous medium laden with a volatile constituent from the region of the cell intermediate the spinning die and the point of exit of the filament or thread from the cell.

15. The process of manufacturing filaments or threads by dry spinning which comprises causing a viscous fluid'to be extruded from a spinning die in an evaporativeratmosphere in a closed cell, admitting a gaseous medium into the cell in the vicinity of the die, withdrawing the gaseous medium laden with a volatile constituent from a region of the cell intermediate the spinning die and the point of exit of the filament or thread from the cell, and admitting a gaseous medium in the region of the cell where the thread issues therefrom.

16. The process of manufacturing filaments or threads by dry spinning which comprises causing a viscous fluid to be extruded from a spmn mg die into an evaporative atmosphere in a closed cell, admitting a gaseous medium into the cell in the vicinity of the-spinning die, withdrawing the gaseous mediumladen with a volatile constituent from a region of the cell intermediate the spinning die and the point of exit of the filament or thread from the cell, and admitting a gaseous medium in the region where the thread issues from the cell, said gaseous medium being of different composition from that admitted in the vicinity of the die.

17 An apparatus for manufacturing filaments or threads by dry spinning comprising a closed cell, a single spinning die disposed in said cell, means for admitting a gaseous medium in the vicinity ofthe die, andmeans to admit a gaseous medium in the region of the tfzgll where the thread or filament issues thereom. I

18. An apparatus for manufacturing filaments or threads by dry spinning comprising a closed cell, a single spmnmg die disposedv in said cell, means for admitting a gaseous medium 111t 0' the cell in the vicinity of the spmmngdie, means for withdrawing the gaseous medium laden with a volatile constituent from a region of the cell intermediate the spinning die and the point of exit of the filament or thread from the cell, and means to'admit agaseous medium in the region of the cell where the thread issues therefrom.

19. An apparatus for manufacturing filaments or threads by dry spirming comprising spinning die directly into an evaporative ata closed cell, aspinning die disposed in said cell, means for simultaneously lowering the temperature of the fluid to be spun before it reaches the die and of the atmosphere in the vicinity of the die, and means to admit a gaseous medium in the region of the'cell where the thread issues therefrom.

20; A method of manufacturing filaments and threads by the dry spinnin process which comprises'causing a viscous uid to be extruded from a spinning die directly into an evaporative atmosphere in a closed cell individual to said die introducing a gaseous medium in the vicinity of the d1e,causing said medium to travel in the direction of the thread and withdrawing said medium laden with solvents at a point intermediate the die anlrli the place where the thread leaves the ce 21. The process of manufacturing filaments or threads by dry spinning which comprlses causing a VlSCO'llS fluid to be extruded from a splnning die into an evaporative atmosphere in a closed cell individual to said spinning die, admittinga cooled gaseous medium in the vicinity of the die to lower the temperature of the atmosphere in the vicinity of the die Withdrawing the gaseous medium laden with a volatile constituent from the region of the cell intermediatethe die and point of exit of the thread from the cell and winding the thread after it leaves the cell.

22. The process of manufacturing filaments or threads by dry s inning which comrises causing a viscous uid to be extruded mm a spinnlng d e into an evaporative atmosphere in a closed cell individual to said die, admitting a gaseous medium into the cell in the vicinity of the spinning die, withdrawing the gaseous medium laden with a volatile constituent from the region of the cell intermediate the die and point of exit of the thread from the cell, admitting a gaseous medium to the cell in the region where the filament or thread issues therefrom and winding 7 the thread after. it leaves the cell.

In testimony whereof, I affix my signature.

EDMOND PRINCE. 

